The use of P-channel metal oxide semiconductor field effect transistors (P-channel MOSFETs) for high side drivers has been limited to low voltage applications traditionally, typically for voltages under 20 volts. This is due to the breakdown of the P-channel MOSFET gate at high voltages, which typically limits the use of P-channel MOSFETs to situations where the Vgs is +/−20 volts. Other approaches for driving high voltage P-channel MOSFETs often suffer other undesirable limitations such as limited switching speed and low or underutilized duty cycles. Often, the most common approach to high side and high voltage MOSFET switching is employing an N-channel MOSFET with commercially available drivers for level shifting. However, this approach is not without drawbacks. N-channel MOSFETs require a separate floating power supply for each MOSFET. Not only does this add to complexity in manufacturing and operating, but it also increases costs as more parts are required to operate N-channel MOSFET high side drivers. Using commercially available IC (integrated circuit) drivers also has disadvantages. Commercially available ICs often have duty cycle limitations of less than 100%. There are also other IC chips with charge pumps for level shifting, but the gate drive current is often limited to accommodate smaller size power MOSFETs. Further, these charge pump N-channel driver IC chips are often limited to a maximum of 80 volts.
Because of the limitations of the prior art, it is desirable to have a system for high voltage level switching using P-channel MOSFET which is capable of high speed switching frequency as well as having fewer floating power sources.